molly-file/module/file_handler.js

molly-file is a free and opensource

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const fetch = require('molly-fetch');
const rdl = require('readline');
const http = require('http');
const fs = require('fs');

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function multiwrite( chunk, ...output ){
    for( let out of output ){ 
        if( !out.writableEnded )
             out.write(chunk)
    }
}

function multiclose( chunk, ...output ){
    for( let out of output ){ 
        if( !out.writableEnded )
             out.end(chunk)
    }
}

function multipipe( input, ...output ){

    input.on('data',(chunk)=>{ 
        for( let out of output ) {
            if( !out.writableEnded )
                 out.write(chunk)
        }
    });

    input.on('close',()=>{
        for( let out of output ) {
            if( !out.writableEnded )
                 out.end()
        }
    });

    input.on('error',()=>{
        for( let out of output ) {
            if( !out.writableEnded )
                 out.end()
        }
    });

}

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function isChunkFinished( path ){
    return new Promise(async(response,reject)=>{

        function wait(time){
            return new Promise((response,reject)=>{
                setTimeout(response,time);
            });
        } 

        function getContentLength(){
            return new Promise((response,reject)=>{
                const itf = rdl.createInterface({ 
                    input: fs.createReadStream( path )
                });

                itf.on('line',(line)=>{
                    if( !line.length ) return itf.close();
                    if( (/content-length/gi).test(line) )
                        response( +line.match(/\d+/gi)[0] )
                });

                itf.on('close',()=>{ response(0) });
            });
        }

        let prev = fs.statSync(path).size;
        let size = await getContentLength();

        let i=0; while( true ){
            const n_prev = fs.statSync(path).size;
            if( !size || !prev ) return reject();
            if( size < prev ) return response();
            if( i > 4 ) return reject(); 
            if( prev == n_prev ) i++; 
                await wait(1000); 
                prev = n_prev;
        }

    });
}

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module.exports = function(obj,cli){

    function send( res ){
        const wrt = fs.createWriteStream( obj.path );
        const status = http.STATUS_CODES[res.status];
        multiwrite(`${obj.ptr} ${res.status} ${status}\r\n`,cli,wrt);
        for( const x of Object.keys( res.headers ) ){
            if( (new RegExp('transfer-encoding','gi')).test(x) ) continue;
            if( Array.isArray(res.headers[x]) ) for( const y of res.headers[x] )
                 multiwrite(`${x}: ${res.headers[x][y]}\r\n`,cli,wrt);
            else multiwrite(`${x}: ${res.headers[x]}\r\n`, cli,wrt);
        }   multiwrite('\r\n',cli,wrt); multipipe(res.data,cli,wrt);
    }

    function end( res ){
        const status = http.STATUS_CODES[404];
        cli.write(`${obj.ptr} 404 ${status}\r\n`);
        cli.write('contet-type: text/plain\r\n');
        cli.end('\r\nurl not supported');
    }

    function str(){
        fetch(obj).then(res=>{ send(res) }).catch(rej=>{
			try {
				if( rej.headers['range'] && !(/text/i).test(rej.headers['content-type']) ) 
					rej.status = 100; send(rej);
			} catch(e) { end() }
        })
    }

    if( !fs.existsSync( obj.path ) ){
         fs.writeFileSync( obj.path,'' ); return str();
    } isChunkFinished(obj.path).then(()=>{
        const rdb = fs.createReadStream(obj.path);
              rdb.pipe(cli);
    }).catch(()=>{ str() });

}

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